Performance of a wireless communication system is affected by conditions of wireless channels to a great extent, such as shadow fading and frequency selective fading, and it is required to perform channel estimation so as to recover accurately transmitted signals from a transmission end. In an existing channel estimation mode, influence of sampling offsets on whole performance of a system is generally not taken into consideration during a noise reduction process in post processing of the channel estimation, signal side lobes are also removed when noises are eliminated, thus resulting in poor performance of a receiver.
Channel estimation of a Wideband Code Division Multiple Access (WCDMA) system or a Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) system is taken as an example, a conventional channel estimation involves that Fast Fourier Transform (FFT) is performed firstly in frequency domain, then a time-domain channel estimation value is obtained through Inverse Fast Fourier Transform (IFFT), and noise influence is eliminated through post processing in which sampling offsets of the receiver are not taken into consideration, and signal side lobes are inevitably eliminated together with the elimination of noises, because during a noise elimination process of channel estimation, due to a relatively fast attenuation of the signal side lobes with respect to that of the main lobe and relatively small energy of the side lobes, particularly in cases where the SNR is not very high, the energy of the side lobes is overwhelmed in the noises, thus the signal side lobes are eliminated when the noises are eliminated. This processing method has its disadvantages: it firstly lacks a corresponding processing of sampling offsets, thus energy of received signals will be lowered and the reception SNR will be reduced; secondly, interferences resulted from signal side lobes are not taken into consideration, thus quality of the received signals are deteriorated and performance of the receiver is lowered.